这些你都知道吗？以后给老外作报告的时候可千万别再“Theequationislikethis…”,“Thevalueislikethis…”有些公式不好写，能看出来什么意思就行了。1.Logic∃thereexist∀forallp⇒qpimpliesq/ifp,thenqp⇔qpifandonlyifq/pisequivalenttoq/pandqareequivalent2.Setsx∈AxbelongstoA/xisanelement(oramember)ofAx∉AxdoesnotbelongtoA/xisnotanelement(oramember)ofAA⊂BAiscontainedinB/AisasubsetofBA⊃BAcontainsB/BisasubsetofAA∩BAcapB/AmeetB/AintersectionBA∪BAcupB/AjoinB/AunionBA\BAminusB/thediferencebetweenAandBA×BAcrossB/thecartesianproductofAandB3.Realnumbersx+1xplusonex-1xminusonex±1xplusorminusonexyxy/xmultipliedbyy(x-y)(x+y)xminusy,xplusy=theequalssignx=5xequals5/xisequalto5x≠5x(is)notequalto5x≡yxisequivalentto(oridenticalwith)yx>yxisgreaterthanyx≥yxisgreaterthanorequaltoyx<yxislessthanyx≤yxislessthanorequaltoy0<x<1zeroislessthanxislessthan10≤x≤1zeroislessthanorequaltoxislessthanorequalto1|x|modx/modulusxx2xsquared/x(raised)tothepower2x3xcubedx4xtothefourth/xtothepower4xnxtothenth/xtothepowernx(−n)xtothe(power)minusnx的平方根(square)rootx/thesquarerootofxx的三次根cuberoot(of)xx的四次根fourthroot(of)xx的n次根nthroot(of)x(x+y)2xplusyallsquaredn!nfactorialx^xhatx¯xbarx˜xtildexixi/xsubscripti/xsuffixi/xsubi∑(i=1~n)aithesumfromiequalsonetonai/thesumasirunsfrom1tonoftheai4.Linearalgebra‖x‖thenorm(ormodulus)ofxOA→OA/vectorOAOA¯OA/thelengthofthesegmentOAATAtranspose/thetransposeofAA−1Ainverse/theinverseofA5.Functionsf(x)fx/fofx/thefunctionfofxf:S→TafunctionffromStoTx→yxmapstoy/xissent(ormapped)toyf’(x)fprimex/fdashx/the(first)derivativeoffwithrespecttoxf”(x)fdouble-primex/fdouble-dashx/thesecondderivativeoffwithrespecttoxf”’(x)triple-primex/ftriple-dashx/thethirdderivativeoffwithrespecttoxf(4)(x)ffourx/thefourthderivativeoffwithrespecttox∂f/∂x1thepartial(derivative)offwithrespecttox1∂2f/∂x12thesecondpartial(derivative)offwithrespecttox1∫0∞theintegralfromzerotoinfinitylimx→0thelimitasxapproacheszerolimx→0+thelimitasxapproacheszerofromabovelimx→0−thelimitasxapproacheszerofrombelowlogeylogytothebasee/